Conventional pressure feed pumps provided for feeding ready mixed concrete can be classified into:
1. Compressed air type, PA1 2. Tube type, and PA1 3. Plunger type.
These types of pressure feed pumps are all defective because of complicated structure, intermittent feed, and low efficiency.
On the other hand, a conventional screw pump having a revolving blade extending helically can feed fluid continuously and efficiently.
However, the conventional screw pump is defective in that when fed through, ready mixed concrete, adhesive fluids, or sticky materials clog in the revolving blade sections of the screw to turn together with the revolving blade in the outer cylinder; that is, the screw pump would not be capable of feeding the materials due to clogging. This results in clogging of the materials.
Moreover, the conventional screw pump is still deffective in that aggregate including stone, gravel, and the like are bit (clipped) in between an edge of the revolving blade thereof and the inside of the outer cylinder thereof. It has not been possible to use the conventional screw pump for feeding the ready mixed concrete and the like.
Therefore, it is an object of the present invention to provide a screw pump which can effectively and securely feed ready mixed concrete, gravel, clay, viscous fluids such as starch syrup and glucose, and sticky materials such as malt and yeast.
It is an another object of this invention to provide a pressure feed screw pump which can prevent the aggregate from being bit in between the outer cylinder and the revolving blade of the screw, and allows the ready mixed concrete to be fed by the screw continuously and effectively.